Carpets are typically constructed from a primary backing material and a face pile formed on one side. Face pile can be form in the primary backing by tufting or by adhesively attaching a face pile to the primary backing. Currently, the majority of carpet being manufactured in the U.S. is made by a tufting process. The tufting process forms looped or cut pile on one side of a primary backing and loop backs on the opposite side by a process well known in the art. The primary backing can be made from a woven or nonwoven fabric of natural or synthetic materials. Synthetic turf is also made by tufting synthetic filaments into a synthetic primary backing.
After the primary backing is tufted, an adhesive precoat may be applied to lock the tufts in the primary backing. Then, a secondary backing may optionally be adhesively attached by applying a coating of adhesive on the side of the primary backing opposite the face pile, contacting the adhesive with the secondary backing and allowing the adhesive to cool or cure.
An adhesive frequently used as an adhesive pre-coat or for attaching a secondary backing to a primary backing is polyurethane. However, polyurethane generally is not recyclable. To solve the problem of non-recyclability, thermoplastic adhesives have been used. However, attaching a secondary backing to a primary backing with a hot melt thermoplastic adhesive generally requires relatively large amount of adhesive. This relatively large amount of adhesive contributes to the overall cost of the finished product.
It would be desirable to be able to attach a secondary backing to a primary backing of a carpet or synthetic turf using an adhesive system that requires the use of relatively smaller amounts of adhesive. It would also be desirable to be able to attach a secondary backing to a primary backing of a carpet or synthetic turf using reduced amounts of adhesive without sacrificing desired physical properties of the finished product.